Multi-wheeled excavating and loading system

ABSTRACT

In an excavating and loading system, an excavating wheel assembly comprises three excavating wheels each having a plurality of digging buckets. Each digging bucket is moved to the material receiving position during movement of the digging bucket through an initial portion of its rotation and to the material discharging position during a subsequent portion of its rotation. Material discharged from the digging buckets of the excavating wheel assemblies is received by conveyors and is transported thereby upwardly and rearwardly to a discharge point at the rear of the vehicle. The two outside excavating wheels of the excavating wheel assembly may be equipped with conical cutting members, whereby the excavation formed by the excavating and loading system is provided with tapered side walls.

United States atent Satterwhite July 29, 1975 [54] MULTI-WHEELEDEXCAVATING AND 3,690,023 9/ 1972 Peterson 37/ 190 X LOADING SYSTEMFOREIGN PATENTS OR APPLICATIONS [75] Inventor: Charles R. Satterwhite,Dallas, Tex. 137,833 2/1956 U.S.S.R 37/190 992,676 5/1965 U 'ted Kin d37/190 [73] Asslgnee Swihwes Equ'pmem Devehpers 1,028,944 4/1958Gigi-many 37/190 Inc-r Dallas 458,534 4 1928 Germany 37/190 I 7 590,8531/1934 Germany 37/190 [22] Flled Sept 2 l9 3 900,536 12/1953 Germany37/190 [21] Appl. No.: 400,043

Related Us. Application Data Primary Examiner-Clifford D. CrowderAttorney, Agent, or Firm-Richards, Harris & [63] Contmuation-in-part ofSer. No. 238,089, March 28, Medlock 1972, abandoned.

52 us. c1. 299739; 37/190; 37/DIG. 16; 1571 ABSTRACT 172/124; 299/67;299/89 In an excavating and loading system, an excavating [51] Int. ClE02f 3/24 wheel assembly comprises three excavating wheels [58] Field ofSearch 37/189, 190, 91, 94-97, each having a plurality of diggingbuckets. Each dig- 37/DIG. 16; 299/39, 53, 54, 75, 76, 78, 67, gingbucket is moved to the material receiving posi- 89; 198/9; 172/124 tionduring movement of the digging bucket through an initial portion of itsrotation and to the material dis- [56] References Cited chargingposition during a subsequent portion of its UNITED STATES PATENTSrotation. Material discharged from the digging buckets 109 273 11/1870Thompson 172 124 x of the excavating Wheel assemblies is received by 1005 544 10/1911 Henderson 37/189 "eyms and is transpmted therebyupwardly and 1:284:041 11/1918 Bager............: 37/D1G. 16 wardly adischarge Point at the rear of the vehicle 1,336,657 4/1920 Schmidt..37/189 The two outside excavating wheels of the excavating 1,858,3275/1932 Hays 37/190 X wheel assembly may be equipped with conical cutting2,748,505 6/1956 Turner.... 37/96 members, whereby the excavation formedby the exca- 2,984,025 5/1961 Winn 37/DIG- l6 vating and loading systemis provided with tapered 3,052,455 9/1962 McLaughlin et a1 299/76 Sidewalls 3,101,932 8/1963 Wright 37/189 X 3,230,647 1/1966 Gates 37 190 45Claims, 17 Drawing Figures N 354 27 290\ x 0 Q I I 2 298 334 i 344 ,1 e300 j ,Js-

274 I ll F 296 41, i

302 21:12 fl'\ x E :3/6 I y I, I) ""-\I2 rs i! I 1 3 4 \1 332 P 4.5 1 r-1 k 7 v 8, 222- 316 1 PATENTEDJULZQIHYS 3, 897, 109

SHEET 1 FIG. 3

PATENTED JUL 2 9 I975 SHEET PATENTED JUL29 1975 SHEET PATENTEU JUL 2 9I975 SHEET PATENTED JUL 2 9 I975 SHEET SHEET PATENTEI] JUL 2 9 I975 FIG.[4

FIG. l5

PATENTED JUL 2 9 I975 SHEET FIG. I6

FIG.

MULTI-WHEELED EXCAVATING AND LOADING SYSTEM CROSS-REFERENCE TO RELATEDAPPLICATION This application is a continuation-in-part of copendingapplication Ser. No. 238,089, filed Mar. 28, 1972, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates toexcavating and loading systems, and more particularly to an improvedexcavating and loading system of the excavating wheel type.

Although an almost infinite number of excavating and loading systemshave been designed heretofore, the need persists for considerableimprovement in the art. For example, a typical loading machine availableat the present time is capable of loading up to 1,700 cubic yards ofearth per hour, has a gross weight of approximately 250,000 pounds, andsells for approximately $330,000. Furthermore, notwithstanding thisrelatively high cost and relatively low capacity, such a device isincapable of either ditching or forming a finished grade.

The present invention comprises a novel excavating and loading systemwhich overcomes the disadvantages that have characterized the prior art.Thus, in one embodiment of the invention there is provided a machinecapable of loading up to 4,000 cubic yards of earth per hour, having agross weight of about 100,000 pounds, and having a selling price ofapproximately $150,000. Perhaps more importantly, excavating and loadingsystems incorporating the invention are capable of forming a finishedgrade in a single pass.

In accordance with the broader aspects of the invention an excavatingand loading system comprises a vehicle, an excavating wheel assemblymounted at one end of the vehicle, and a conveyor which extends upwardlyfrom a material receiving portion adjacent the wheel assembly to amaterial delivery portion at the opposite end of the vehicle. Theexcavating wheel assembly is greater in width than the remainingcomponents of the system and comprises a plurality of digging bucketseach including a wall which is supported for pivotal movement between amaterial receiving position and a material dumping position. Structureis provided for rotating the excavating wheel assembly and for operatingthe movable walls of the buckets to first receive material and tosubsequently dump the material into the material receiving portion ofthe conveyor.

In accordance with a first embodiment of the invention, the vehiclecomprises a main frame which is supported by a plurality of tiredwheels. A first engine is supported on the main frame and functions toactuate the wheels to propel the vehicle and to actuate the conveyor totransport material thereon from the material receiving portion to thematerial delivery portion. A subframe is mounted at the top of the frontend of the main frame and the excavating wheel assembly is rotatablysupported on the subframe. The subframe also supports a second engineand a transmission which operatively interconnects the second engine andthe excavating wheel assembly. An auxiliary conveyor is detachablysupported at the rear of the main frame for receiving material from thedelivery end of the conveyor and for transporting the material eitherrearwardly or laterally. A plurality of ballast tanks are mounted on themain frame for receiving liquid to counterbalance the weight of theauxiliary conveyor.

The excavating wheel assembly preferably comprises a center wheel and apair of side wheels which are supported on the subframe for rotationabout a common axis. In such a case cross conveyors are provided fortransporting material from the side wheels to the material receivingportion of the main conveyor. The first engine preferably driveshydraulic pumps. This permits actuation of the propelling wheels, themain conveyor, the auxiliary conveyor, the auxiliary conveyorpositioning means, and the cross conveyors by hydraulic motorsoperatively connected to the pumps.

In accordance with a second embodiment of the invention a motor ismounted on the subframe instead of the second engine, the verticalpositioning of the material delivery portion of the main conveyor islowered. and the auxiliary conveyor is removed. Structure is providedfor pivoting the subframe to position the excavating wheel above andbelow the highest and lowest elements of the system, respectively. Thispermits use of the excavating and loading system in tunnelingoperations.

In accordance with a third embodiment of the invention the excavatingwheel assembly is mounted on a subframe extending from the bottom of thefront end of the vehicle. The vehicle is supported on tracks, andapparatus is provided for propelling the vehicle, actuating theconveyor, and actuating the excavating wheel assembly by means of asingle engine. This embodiment of the invention also illustrates analternative use of the excavating and loading system wherein theexcavating wheels are rotated downwardly. This facilitates excavation ofasphalt and similar materials in the form of relatively small pieces, asopposed to large plate-like sections of the material which might beencountered if the excavating wheels were rotated upwardly.

In accordance with a fourth embodiment of the invention the axis ofrotation of the three excavating wheels comprising the excavating wheelassembly is offset angularly with respect to a line extendingperpendicularly to the longitudinal axis of the vehicle. This is toprevent the formation of ridges between the excavating wheels during theuse of the excavating and loading system in hard materials. In theoperation of any of the various embodiments of the invention, theoutside excavating wheels of the excavating wheel assembly may beequipped with cone-shaped cutter members, whereupon the excavationformed by the excavating and loading system is provided with taperedside walls.

DESCRIPTION OF THE DRAWINGS A more complete understanding of theinvention may be had by referring to the following detailed descriptionwhen taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of an excavating and loading system comprising afirst embodiment of the invention;

FIG. 2 is a partial top view of the excavating and loading system shownin FIG. 1;

FIG. 3 is a partial front view of the excavating and loading system;

FIGS. 4, 5 and 6 are enlarged side views of the rear, central, andforward portions of the excavating and loading system, respectively;

FIGS. 7 through 12 are illustrations of various systems for actuatingthe rear plates of the digging buckets of an excavating and loadingsystem incorporating the invention;

FIG. 13 is a side view of an excavating and loading system comprising asecond embodiment of the invention;

FIG. 14 is a side view of an excavating and loading system comprising athird embodiment of the invention;

FIG. 15 is an enlarged side view of the forward portion of theexcavating and loading system shown in FIG. 14;

FIG. 16 is a top view of the forward portion of an excavating andloading system incorporating a fourth embodiment of the invention; and

FIG. 17 is an illustration of conical cutter members which may beutilized in conjunction with any of the various embodiments of theinvention.

DETAILED DESCRIPTION Referring now to the drawings, and particularly toFIGS. 1 and 4 through 6, an excavating and loading system 20incorporating a first embodiment of the invention is shown. The system20 comprises a vehicle 22 including a main frame 24 which is supportedby four wheels 26 for movement along a surface S. Each of the wheels 26comprises a pneumatic tire 28 whereby the excavating and loading system20 is adapted for movement over highways and other paved surfaces aswell as for operation in unpaved areas, such as during an excavatingoperation.

A first engine 30 is supported on the main frame 24 of the vehicle 22.In accordance with the preferred embodiment of the invention, the firstengine 30 is an internal combustion engine and functions to drive aplurality of hydraulic pumps 32. The pumps 32 in turn supply operatingpower for various components of the excavating and loading system 20.For example, one of the pumps 32 supplies operating power for ahydrostatic drive 34. The hydrostatic drive 34 is coupled to atransmission 36 including a brake 38. The transmission 36 provides dualoutputs which are coupled to a forward differential 40 and a reardifferential 42 by a plurality of drive shafts 44. Thus, the hydrostaticdrive 34 operates by means of the wheels 26 to propel the excavating andloading system 20 both during excavating operations and during travel.

An excavating system comprises the forward portion of the excavating andloading system 20. The excavating system 50 includes a subframe 52 whichis supported on a shaft 54 for pivotal movement relative to the vehicle22 under the action of a pair of hydraulic cylinders 56. Operating powerfor the cylinders 56 is supplied by one of the pumps 32 which are drivenby the first engine 30.

The excavating system 50 further includes an excavating wheel assembly58 which is supported at the front end of the subframe 52. Theexcavating wheel assembly 58 is driven by a second internal combustionengine 60 which is supported at the rear end of the subframe 52. Theengine 60 provides operating power for the excavating wheel assembly 58but otherwise plays no part in the operation of the excavating andloading system 20. This arrangement has been found to be highlysatisfactory for two reasons. First, it permits selection of the secondengine 60 on the basis of the power requirements of the excavatingsystem 50 only and not on the basis of the power requirements of theother components of the excavating and loading system 20. Also, due toits positioning at the rear of the subframe 52, the second engine 60acts as a counterbalance for the weight of the excavating wheel assembly58. This permits the use of hydraulic cylinders 56 of reduced size andalso reduces the amount of power that is required in manipulating theexcavating wheel assembly 58.

As is best shown in FIG. 6, a crumbing shoe 62 is supported at the frontend of the vehicle 22 of the excavating and loading system 20 beneaththe excavating wheel assembly 58. The crumbing shoe 62 is connected tothe vehicle 22 by a pair of turnbuckles 64 and is also connected to thesubframe 52. By this means the positioning of the subframe 52 under theaction of the hydraulic cylinders 56 automatically correctly positionsthe crumbing shoe 62.

Referring now to FIGS. 2, 3 and 6, the excavating wheel assembly 58comprises three excavating wheels 66A, 66B, and 66C, which are rotatablysupported on the subframe 52 by a shaft 68 and a plurality of bushings70. The secone engine 60 drives a speed reducer 72 which in turn drivesa right angle drive 74. The right angle drive 74 actuates a pair ofchain and sprocket drives 76 each including a sprocket 78 driven by theright angle drive 74, a chain 80 driven by the sprocket 78, and asprocket 82 driven by the chain 80. As is best shown in FIG. 6, thechains 80 and the sprockets 82 are mounted within the subframe 52 andare therefore protected from damage due to accumulations of dirt, etc.,during the operation of the excavating and loading system 20.

Each sprocket 82 is mounted on a shaft 84 which is rotatably supportedin the subframe 52 and which in turn supports a pair of pinions 86. Thepinions 86 are each mounted in mesh with a ring gear 88 mounted on oneof the wheels 66 whereby the second engine 60 functions to rotate thewheels. In accordance with the preferred embodiment of the invention,the center excavating wheel 66B is provided with two ring gears 88 andis driven by two pinions 86, whereas the side excavating wheels 66A and66C support a single ring gear 88 and are driven by a single pinion 86.

The excavating wheels 66 of the excavating wheel assembly 58 eachinclude a hub 90 and a pair of rims 92 which extend radially outwardlyfrom the hub. The excavating wheels comprise a plurality of diggingbuckets 94 which are equally spaced circumferentially around the hub 90and which extend between the rims 92. The digging buckets 94 each have acutting edge 96 including a plurality of teeth 98 and a stationary frontwall 100 extending generally radially inwardly from the cutting edge 96.Each digging bucket further includes a rear wall 102 which is supportedfor pivotal movement between a digging position and a dumping position.The rear walls 102 of the digging buckets 94 are actuated by one of themechanisms shown in FIGS. 7 through 12 and are manipulated thereby tothe digging position when their respective digging buckets 94 are in thelower and forward portion of their rotary motion and to the dumpingposition when their respective digging buckets are in the upper andrearward portion of their rotary motion.

As is clearly shown in FIGS. 2 and 3, the three wheels 66A, 66B, and 66Ccomprising the excavating wheel assembly 58 have an overall width whichexceeds that of the remaining components of the excavating and loadingsystem 20. This has been found to be highly advantageous for tworeasons. First, by increasing the width of the excavating wheel assembly58 over that of a conventional ditching machine, an excavating andloading system incorporating the present invention is capable ofexcavating considerably more material with out increasing the speed ofrotation of the excavating wheel assembly. Second, the fact that theexcavating wheel assembly 58 is wider than the remaining components ofthe excavating and loading system permits operation of the excavatingand loading system within the excavation that is being formed. Thismaterially reduces the amount of movement of the excavating wheelassembly 58 that is necessary to position the assembly for excavatingand for travel, and thereby reduces the overall complexity of anexcavating and loading system incorporating the invention.

The excavating and loading system 20 further includes a loading system110. The loading system includes a main conveyor 112 comprising anendless belt 114 mounted for movement around a course extendingangularly upwardly relative to the main frame 24 of the vehicle 22 andincluding a material receiving portion 116 and a material deliveryportion 118. More particularly, the course of the belt 114 is defined bya plurality of rollers 120 which are supported on a conveyor frame 122.The conveyor frame 122 is supported on the main frame 24 of the vehicle22 and includes an upper portion 124 supported for pivotal movementabout a horizontal axis under the action of a hydraulic cylinder 126.This permits control over the vertical positioning of the materialdelivery portion 118 of the conveyor 112.

The belt 114 of the main conveyor 112 extends around a relatively smalldrum 128 mounted at the upper end of the frame 122 and around arelatively large drum 130 mounted on the frame 24. The drums 128 and 130are rotated by radial hydraulic motors 132 and 134, respectively. Bythis means the belt 114 is actuated for movement around the coursedefined by the rollers 120 to move material from the material receivingportion 116 to the material discharge portion 118. It has been foundthat the positioning of the drums 128 and 130 causes a synergisticeffect in that the drum 130 functions to cause the belt 114 to wrap moretightly around the drum 128 and thereby increase the effectiveness ofthe motor 132 in moving the belt 114.

A pair of cross conveyors'140 are also supported on the main frame 24 ofthe vehicle 22. The cross conveyors are driven by hydraulic motors 142and function to receive material from the side excavating wheels 66A and66C and to deliver the material to the material receiving portion 116 ofthe main conveyor 112. By this means all material that is excavated bythe excavating wheel assembly 58 is delivered to the main conveyor 112for transportation thereby from the material receiving portion 116 tothe material discharge 118.

Referring now particularly to FIGS. 1 and 4, the preferred embodiment ofthe invention further includes an auxiliary conveyor system 150. Theauxiliary conveyor system includes a frame 152 which is secured to therear end of the frame 24 of the vehicle 22 by a plurality of pins 154. Aturntable 156 is supported on the frame 152 for pivotal movement about avertical axis under the action of a hydraulic motor 158.

A conveyor 160 is supported on the turntable motor 156 to receivematerial discharged from the material discharge portion 118 of the mainconveyor 112. The conveyor 160 comprises a frame 162 which is supportedon the turntable 156 and an endless belt 164 mounted for movement arounda course defined by a plurality of rollers 166. The belt 164 is drivenby a radial hydraulic motor 168, and a hydraulic cylinder is providedfor controlling the angular relationship of the frame 162 to theturntable 156.

The auxiliary conveyor system 150 further includes a conveyor 172comprising a frame 174 which is supported on the frame 162 of theconveyor 160 by a pair of parallel links 176. An endless belt 178 issupported on the frame 174 for movement around a course defined by apair of drums 180. The conveyor 178 is driven by small hydraulic motors(not shown) mounted in the drums 180.

A hydraulic cylinder 182 extends between the frame 162 of the conveyor160 and the frame 174 of the conveyor 172 for actuation to manipulatethe conveyor 172 between the positions shown in full and in dashed linesin FIG. 4. When the conveyor 172 is positioned as shown in full lines inFIG. 4, it functions to receive material from the conveyor 160 and todischarge the material from the end of the excavating and loading system20 remote from the excavating system 50. On the other hand, when theconveyor 172 is positioned as shown in dashed lines in FIG. 4 materialis discharged directly from the conveyor 160. This arrangement is highlyadvantageous in that it permits the positioning of a dump truck orsimilar vehicle under the discharge end of the conveyor 160 whileanother vehicle is being loaded from the conveyor 172, and vice versa.

It will be appreciated that the hydraulic motor 158 may be actuated topivot the turntable 156 and the conveyors 160 and 172 supported thereonthrough an arc of approximately The excavating and loading system 20 mayalso be operated with the auxiliary conveyor system 150 removed, ifdesired. These conditions cause substantial changes in the overallweight distribution of the component parts of the excavating and loadingsystem 20.

As is best shown in FIGS. 1 and 2, the vehicle 22 is equipped with acounterbalancing system comprising four ballast tanks 192, 194 196 and198 located at forward and rearward positions on opposite sides of thevehicle 22. In the use of the excavating and loading system 20, water isselectively pumped to and from the tanks comprising the counterbalancingsystem 190 whereby changes of the weight distribution of the excavatingand loading system 20 caused by manipulations of the auxiliary conveyorsystem 150 are compensated for. Thus, if the excavating and loadingsystem 20 is operated with the auxiliary conveyor system 150 removed,water is pumped out of the tanks 194 and 198 and into the tanks 192 and196. Similarly, if the hydraulic motor 158 is operated to pivot theauxiliary conveyor system 150 towards one side of the vehicle 22, thetanks on the opposite side of the vehicle are filled with water wherebythe change in weight distribution caused by the manipulation of theauxiliary conveyor system 150 is completely counterbalanced.

All of the hydraulic motors and all of the hydraulic cylinderscomprising the loading system 110 are operatively connected to the pumps32 which are driven by the first engine 30. Thus, the excavating andloading system 20 comprises separate excavating and loading systems 50and 110, respectively, which are driven by independent power sources.This arrangement has been found to be advantageous in that it permitsoptimum utilization of both systems. For example, in certain instancesit may be necessary to provide maximum operating power to the excavatingsystem 50 and to simultaneously provide maximum operating power to theloading system 110. Such a situation is accommodated much more readilyby means of the present invention than would otherwise be possible.

Various systems for actuating the rear walls 102 of the digging buckets94 of the excavating wheels 66A. 66B, and 66C are shown in FIGS. 7through 12. In each instance the rear wall actuating system is locatedentirely within the margins of the excavating wheels. This may becompared with certain prior art systems characterized by external bucketwall actuating apparatus.

Referring particularly to FIG. 7, an actuating system 200 comprises aplurality of push rods 202 each of which is connected between one of therear walls 102 and a chain 204. The chain 204 is generally unconstrainedbut extends around a roller 206 which is supported on the shaft 68 andwhich is secured against angular movement relative to the shaft 68 bysuitable brackets (not shown). As the digging wheels are rotated aboutthe shaft 68 under the action of the second engine 60, each push rod 202comes into engagement with the roller 206 whereupon its respective rearwall 102 is pushed outwardly to the material dumping position.Subsequently, as each digging bucket is rotated to the lower and forwardportion of its circular path. the chain operates through the push rod202 to positively return the rear wall 102 to the material diggingposition. This positive actuation of the rear wall 102 in bothdirections has been found to be vastly superior to the arrangement thathas been used heretofore wherein the rear portions were allowed toreturn to the digging position under the action of gravity.

An actuating system 208 that is similar in many respects to the system200 is shown in FIG. 8. The system 208 incorporates a plurality of pushrods 210 each connected between a chain 212 and the rear wall 102 of oneof the digging buckets 94. The principal difference between the system208 and the system 200 is that the chain 212 of the system 208 isequipped with a plurality of rollers 214. The rollers 214 are mountedfor movement around a saddle 216 which is fixed to the shaft 68. By thismeans the rear wall 102 of the digging buckets 94 are positivelyactuated to the dumping position as each bucket is rotated to the upperand rearward portion of its circular path and is positively returned tothe digging position as the bucket is rotated to the lower and forwardportion of its path.

Another actuating system 218 is shown in FIG. 9. The system 218 includesa crank 220 which is fixed to the shaft 68. A collar 222 is rotatablysupported on the crank 220, and a plurality of push rods 224 extend fromthe collar 222 to the rear walls 102 of the digging buckets 94. One ofthe rear walls 102 is connected to the collar 222 by a rod 226 which isfixed to the collar 222. By this means the collar 222 is constrained torotate with the digging wheel whereby the push rods 224 and 226 functionto positively actuate the rear walls 102 to the dumping position whentheir respective digging buckets are in the upper and rearward portionof their travel about the shaft 68 and to positively return the rearwardwalls 102 to the digging position when their respective digging bucketsare in the lower and forward portion of their travel.

Still another actuating system 228 is shown in FIG. 10. The system 228comprises a plurality of cams 230 each fixed to one of the rear walls102 of the digging buckets 94. The cams 230 are positioned forengagement with a roller 232 which is supported on an arm 234 that isfixed to the shaft 68. Each rear wall 102 is also provided with a spring236 which functions to return the rear wall 102 to the digging position.Thus. upon rotation of a particular digging bucket to bring its cam 230into engagement with the roller 232, the rear wall 102 of the diggingbucket is actuated to the dumping position. As soon as the cam 230 comesout of engagement with the roller 232, the spring 236 returns the rearwall 102 to the digging position.

Referring now to FIG. 11, an actuating system 238 is shown. The system238 comprises a cam track 240 which is supported on the shaft 68 andwhich is fixed against rotation with respect thereto. The rear wall 102of each digging bucket 94 is equipped with a cam follower 242 includinga roller 244 mounted in the cam track 240. The shape of the cam track240 is such that each rear wall 102 is actuated to the dumping positionwhen its digging bucket 94 is in the upper and rearward portion of itsrotation about the shaft 68 and is returned to the digging position whenits respective bucket 94 is in the lower and forward portion of itsrotation.

Yet another actuating system 246 is shown in FIG. 12. In accordance withthe system 246 a pneumatic cylinder 248 is provided for actuating therear wall 102 of each digging bucket 94 between the digging and thedumping positions. Each pneumatic cylinder 248 is equipped with a valve250 for controlling the flow of compressed air from a manifold 252 tothe cylinder 248. Each valve 250 is in turn equipped with a cam follower254 which functions to open its respective valve whenever it is movedinwardly.

The cylinders 248 and their respective valves 250 are mounted forrotation about the shaft 68 with the digging buckets 94 comprising theexcavating wheels. A cam 256 is supported in fixed relation to the shaft68. Thus. as each digging bucket rotates into alignment with the cam256, its respective cam follower 254 is actuated by the cam 256. Thisoperates the corresponding valve 250 to admit compressed air to itspneumatic cylinder 248, whereupon the rear wall 102 is actuated to thedumping position. In a particular arrangement shown. the rear walls 102of the digging buckets 94 are returned to the digging position byindividual springs 258. However, it will be understood that theactuating system 246 may be modified to provide for return of the rearwalls 102 under pneumatic action, if desired. It will be furtherunderstood that the cylinders 248 can comprise hydraulic cylindersrather than pneumatic cylinders.

Referring now to FIG. 13, an excavating and loading system 20 comprisinga second embodiment of the invention is shown. The excavating andloading system 20 is similar to the excavating and loading system 20described hereinbefore in that it comprises a vehicle 22. an excavatingsystem 50, and a loading system One difference between the system 20 andthe system 20' is that the first and second engines 30 and 60 of thesystem 20 are replaced with electric motors 30' and 60 in the system20'. Another difference is that the electric motor 60' is positioned ina forward location and in that the angular positioning of the excavatingsystem 50' is controlled by hydraulic cylinders 56 which are arrangedsomewhat differently from the hydraulic cylinders 56 of the excavatingand loading system 20. This permits the cylinders 56' to pivot theexcavating system 50 to points above and below the highest and lowestpoints on the remainder of the excavating system 20 and thereby adaptsthe excavating and loading system 20' to tunneling operations. The useof the excavating and loading system 20' in tunnel ing operations isfurther facilitated by the use of the electric motors 30' and 60 wherebythe emission of dangerous exhaust gases is completely eliminated.

Referring now to FIGS. 14 and 15, there is shown an excavating andloading system 270 incorporating a third embodiment of the invention.The excavating and loading system 270 comprises a vehicle 272 includinga main frame 274 supported on a pair of opposed track assemblies 276 formovement over a surface S. The track assemblies 276 are preferablyconventional in design and comprise a pair of sprockets 278 and 280rotatably supported on a subframe 282 and in turn supporting an endlesstrack 284. Each track assembly 276 further includes at least one motor(not shown) mounted on the subframe 282 and adapted for actuation bymeans of power supplied from a prime mover mounted on the vehicle 272 topropel the vehicle through one of the sprockets and the endless track284 mounted thereon.

Each track assembly 276 is supported for pivotal movement relative tothe main frame 274 of the vehicle 272 about the axis of the rearsprocket 280. A hydraulic cylinder 286 is provided on each side of thevehicle 272 and is connected between the main frame 274 of the vehicleand the subframe 282 of the adjacent track assembly 276. The hydrauliccylinders 286 are preferably actuated in tandem to control the angularrelationship of the track assemblies 276 relative to the remainingcomponents of the excavating and loading system 270.

As will be appreciated by those skilled in the art, the hydrauliccylinders 286 are typically initially actuated to lower the forwardportion of the excavating and loading system 270. This causes theexcavating and loading system to initiate a downwardly inclinedexcavation, whereby the excavating and loading system 270 digs itselfinto the cut or excavation to be formed. When the desired degree ofinclination has been established, the hydraulic cylinders 286 areactuated to re turn the component parts of the excavating and loadingsystem to the orientation illustrated in FIGS. 14 and 15, whereby theexcavating and loading system continues to excavate on the establishedinclination until the desired depth of the excavation is reached.

The hydraulic cylinders 286 are then actuated to cause the excavatingand loading system to form the bottom of the cut or excavation at apredetermined angular relationship with respect to grade. When theexcavation has been finished, the excavating and loading system 270 canbe removed by means of the inclination that was used to dig theexcavation and loading system into the excavation. The hydrauliccylinders 286 may also be utilized to form an upwardly inclined ramp atthe opposite end of the excavation, whereby the excavation and loadingsystem 270 digs itself out of the excavation.

The excavation and loading system 270 further includes an excavatingwheel assembly 290 which is preferably substantially identical inconstruction and operation to the excavating wheel assembly describedhereinbefore in connection with the excavating and loading system 20.Thus, the excavating wheel assembly 290 comprises three excavatingwheels spanning substantially continuously across the front of thevehicle 272 and having an overall width at least equal to that of theremainder of the excavating and loading system. The three excavatingwheels 2992 are all rotatably supported on axles 294 by suitablebushings, and each wheel 292 comprises a series of digging buckets 296which are substantially equally spaced around the periphery of thewheel.

The digging buckets 296 of the excavating wheels 292 comprising theexcavating wheel assembly 290 each comprise a fixed bucket wall 298extending inwardly from a plurality of replaceable digging teeth 300 ofthe type commonly used in excavation equipment. Each bucket 296 alsoincludes a movable wall 302 supported for pivotal movement between amaterial receiving position and a material discharging position. Thus,as each excavating wheel 292 is rotated, the movable wall 302 of eachdigging bucket 296 comprising the wheel is first positively moved to thematerial receiving position and is subsequently moved positively to thematerial discharging position. Any of the various mechanisms illustratedin FIGS. 7 through 12 inclusive may be utilized for the actuation of themovable wall 302 of the digging buckets 296 comprising the excavatingwheel assembly 290 of the excavating and loading system 270.

A major distinction between the excavating system 10 illustrated inFIGS. 1 through 6 and the excavating system 270 illustrated in FIGS. 14and 15 involves the fact that the excavating wheel assembly 290 of theexcavating and loading system 270 is supported on a subframe 310 whichprojects from the bottom of the front end of the vehicle 272 and whichsupports a crumbing shoe 311. The subframe 310 includes spaced, parallelportions 312 which extend between the excavating wheels 292 comprisingthe excavating wheel assembly 290 and which support the excavatingwheels 292 by means of the axles 294. In the embodiment of the inventionillustrated in FIGS. 14 and 15, the subframe 310 is fixedly mounted onthe vehicle 272, and the hydraulic cylinders 286 comprise the sole meansfor adjustment of the inclination of the excavation formed by theexcavating and loading system 270. However, it is also contemplated thatthe subframe 310 may be supported on the vehicle 272 for pivotalmovement under the action of suitable hydraulic actuators connectedbetween the frame 274 of the vehicle 272 and the subframe 310.

The excavating and loading system 270 is further distinguished from theexcavating and loading system 20 in that a single engine 314 mounted onthe vehicle 272 is utilized to supply all of the operating power for theexcavating and loading system 270. The engine 314 drives a plurality ofhydraulic pumps 316, which in turn supply operating power for many ofthe components loading system. The engine 314 further has an outputshaft 318 which extends through a clutch 320 to a universal joint 322.The universal joint 322 connects the shaft 318 to a shaft 324 whichextends to a right angle drive 326. The right angle drive 326 actuates apair of relatively small diameter sprockets 328 which are coupledthrough a pair of chains 330 to a pair of relatively large diametersprockets 332. The sprockets 332 drive a series of sprockets 334 whichare mounted in mesh with ring gears 336 secured on the excavating wheels292. By this means the output of the engine 314 is directly coupled tothe excavating wheel assembly 290 through a drive train extending inpart through the subframe 310 and hence between the three excavatingwheels 292 comprising the excavating wheel assembly.

It will be understood that the spaced, parallel portions 312 of thesubframe 310 comprise hollow boxlike members of the type illustrated inFlGS. 2, 3, and 6 in conjunction with the excavating and loading system20. The spaced, parallel portions 312 therefore serve not only tosupport the excavating wheel assembly 290, but also to enclose thesprockets 328, the chains 330, and the sprockets 332 of the drive systemfor the excavating wheel assembly.

A major design feature of the excavating and loading system 270 involvesthe fact that the excavating wheel assembly 290 is supported on thesubframe 310 by means of three axles 294 which are secured to thespaced, parallel portions 312 of the subframe 310 by means of flanges294', and suitable fasteners. This leaves the interiors of the spaced,parallel portions 312 entirely open, whereby the diameters of thesprockets 332 may be selected to provide the particular speed and torqueinputs to the excavating wheel assembly 290 that are required for agiven excavating situation. On the other hand, if a single axleextending the entire width of the excavating wheel assembly were to beused, the maximum diameter of the sprocket 332 would be substantiallyrestricted.

The ability to vary the speed and torque inputs to the excavating wheelassembly 290 by changing the sprocket wheels 332 has been found tocomprise a substantial advantage. Thus, the operation is carried outquite easily by merely exchanging the sprockets 332 and adjusting thelengths of the chains 330. Moreover, changing the sprockets 332 does noteffect the design criteria of the upstream components of the drivetrain. On the other hand, if another component of the drive train wereto be changed in order to provide required torque and speed inputs tothe excavating wheel assembly 290, various downstream components mightalso have to be changed in order to accommodate increased loads.

The excavating and loading system 270 further includes a loading system340. The loading system 340 comprises a main conveyor 342 which receivesexcavated material directly from the center excavating wheel 292 of theexcavating wheel assembly 290 and which transports the excavatedmaterial upwardly and rearwardly to a discharge point at the extremerear end of the vehicle 272. The system 340 further includes a pair ofcross conveyors 344 which receive excavated material from the twooutside excavating wheels 292 of the excavating wheel assembly 290 andwhich transport the material to the main conveyor 342. As is best shownin FIG. 14, the rear portion of the main conveyor 342 is selectivelypivotable about the axis ofa pin 346 under the action of hydrauliccylinders 348 mounted on the opposite sides of the vehicle 272.

The excavating and loading system 270 may also be provided with anauxiliary conveyor system 350. In such instances the auxiliary conveyorsystem 350 is connected to the extreme rear end of the frame 274 of thevehicle 272 and is utilized either to discharge the excavated materialinto trucks or other vehicles or to discharge the excavated materiallaterally with respect to the excavation being formed. The auxiliaryconveyor system 350 is preferably identical in construction andoperation to the auxiliary conveyor system described in detailhereinbefore in conjunction with the excavating and loading system 20.

An additional feature of the excavating and loading system 270 comprisesan operators compartment 352 positioned at the top of the front end ofthe vehicle 272 to facilitate concurrent observation of all of theoperating instrumentalities of the excavating and loading system 270.The operator's compartment 352 includes the usual operatorss seat 354and a console 356 comprising the usual gauges, switches and controlswhich are necessary for complete regulation of the operation of theexcavating and loading system 270.

FIGS. 14 and 15 further illustrate an alternative usage of excavatingand loading systems incorporating the invention. As will be appreciatedby those skilled in the art, the excavating wheels 292 of the excavatingwheel assembly 290 are so constructed that the orientation of the centerexcavating wheel may be reversed with respect to the axle 294.Similarly. the outside excavating wheel 292 which is usually positionedon the right-hand side of the vehicle 272 may be mounted on theleft-hand side thereof, and the excavating wheel 292 which is usuallymounted on the left-hand side of the vehicle may be mounted on theright-hand side thereof. At the completion of these steps, theexcavating wheels 292 comprising the excavating wheel assembly 290 areoriented as shown in FIGS. 14 and 15. It will be noted'that theorientation of the mechanism which actuates the movable walls 302 of thedigging buckets 296 of the excavating wheels is preferably not changedas the orientation of the excavating wheels 292 is reversed. Thus, eventhough the excavating wheels rotate in the reverse direction, themovable wall 302 of each digging bucket 296 continues to be positivelymoved to the material receiving position as the digging bucket movesthrough the lower forward portion of its rotation and to be positivelymoved to the material discharging position as the digging bucket ismoved through the upper rearward portion of its rotation.

The orientation of the excavating wheels 292 of the excavating wheelassembly 290 in the manner illustrated in FIGS. 14 and 15 is consideredto be particularly advantageous for the excavation of asphalt paving andsimilar materials. Thus, with the excavating wheels so oriented, thedigging teeth 300 of the digging buckets 296 are moved downwardly andtherefore engage the pavement or similar matrerial from above. Thisproduces an anvil effect so that the material is removed in the form ofsmall pieces which are readily handled both by the excavating andloading system 270 and by the trucks or other vehicles which will beutilized to receive the excavated material. Conversely, if theexcavating wheels 292 of the excavating wheel assembly 290 were operatedin the conventional manner with the teeth 300 moving upwardly, theasphalt pavement or similar material might tend to break away in theform of large plate-like sections. Such sections have proven to bedifficult to handle unless they are first further reduced to relativelysmall pieces.

Referring now to FIG. 16, there is shown an excavating and loadingsystem 370 comprising a fourth embodiment of the invention. Theexcavating and loading system 370 comprises a vehicle 372 which ispreferably substantially identical in construction and operation to thevehicle 22 described hereinbefore in conjunction with the excavating andloading system 20. An excavating wheel assembly 374 is supported at thefront end of the vehicle 372 by means ofa subframe 376. The excavatingwheel assembly 374 comprises three excavating wheels 378 extendingsubstantially continuously across the front of the vehicle 372 andhaving an overall width at least equal to that of the remainder of thesystem. The excavating wheels 378 are preferably substantially identicalin construction and operation to the excavating wheels utilized in theexcavating and loading system 20.

In the operation of the excavating and loading system 370, materialexcavated by the center excavating wheel 378 is discharged onto a mainconveyor 380 and is transported thereby to a discharge point at the rearof the vehicle 372. Material excavated by the two outside excavatingwheels 378 is discharged onto a pair of cross conveyors 382 which inturn discharge the excavated material onto the main conveyor 380. Theexcavating and loading system 370 may also be provided with an auxiliaryconveyor system similar to the auxiliary conveyor system 150 of theexcavating and loading system 20, if desired.

The major distinction between the excavating and loading system 370 andthe excavating and loading system comprises the fact that the axis ofrotation of the three excavating wheels 378 comprising theexcavatingwheel assembly 374 is angularly offset with respect to a lineextending perpendicularly to the longitudinal axis of the vehicle 372.This has been found to be advantageous in the excavation of relativelyhard mate rials in that it prevents the formation of ridges in thespaces between the excavating wheels comprising the excavating wheelassembly. The cross conveyors 382 are also angularly offset so as to beproperly positioned to receive material excavated by the two outsideexcavating wheels 378. Nevertheless, the cross conveyors 382 dischargethe excavated material onto the main conveyor 380 which extends parallelto the longitudinal axis of the vehicle 372.

The excavating wheel assembly 374 of the excavating and loading assembly370 is driven by an engine 384 which is mounted on the subframe 3.76 andwhich is positioned so as to counterbalance the weight of the excavatingwheel assembly 374. The engine 384 has an output shaft 386 which iscoupled through a clutch 388 to a speed reducer 390 and hence to a chaindrive 392. The chain drive 392 is in turn coupled through a shaft 394 toa right angle drive 396. The right angle drive 396 in turn functions torotate the excavating wheels 378 of the excavating wheel assembly 374 bymeans of a pair of chain and sprocket drive mechanisms extending betweenthe excavating wheels 378.

Those skilled in the art will appreciate the fact that due to theangularly offset positioning of the excavating wheel assembly 374, theexcavating and loading system 370 functions to form an excavationextending between a plane 398 and a plane 400. This presents no problemexcept for the fact that the portion of the excavation adjacent theplane 398 is formed entirely bythe outside teeth of the excavating wheel378 adjacent thereto. To

this end, the circular outside surface of the excavating wheel 378adjacent the plane 398 may be provided with auxuliary cutting teeth 402which function to assist in the formation of the adjacent portion of theexcavation.

FIG. 17 illustrates an accessory which may be utilized in conjunctionwith any of the various embodiments of the invention describedhereinbefore. Thus, the outside excavating wheels 410 of an excavatingwheel assembly 412 incorporating the invention may be provided withconical cutter members 414. The cutter members 414 are detachablymounted and are preferably provided with replaceable cutting teeth 416of the type commonly utilized in excavating machines of various types.

The purpose of the cutter members 414 is to form tapered side walls onthe opposite edges of a cut or excavation formed by the excavating wheelassemblly 412. Assuming that the overall depth of the excavation doesnot exceed the radius of the excavating wheels 410. the side walls ofthe excavation will be tapered from top to bottom. On the other hand, ifthe total depth of the excavation exceeds the radius of the excavatingwheels 410, only the lower portion of the side walls of the excavationwill be tapered. In either event. it is often advantageous to providetapered side walls on an excavation, particularly in those instances inwhich the material being excavated does not have sufficient substance toretain a vertical side wall configuration.

From the foregoing it will be understood that the present inventioncomprises additional improvements relating to the excavating and loadingsystem disclosed and claimed in the copending application of Charles R.Satterwhite. filed Mar. 28, 1972, Ser. No. 238,089. Thus, in accordancewith the third embodiment of the invention described herein, anexcavating and loading system comprises a vehicle supported on tracksand an excavating wheel assembly supported on a subframe extending fromthe bottom of the front end of the vehicle. A single engine is utilizedto provide operating power for all of the operating components of theexcavating and loading system. The third embodiment of the inventionfurther illustrates how the excavating wheels of an excavating andloading system incorporating the invention can be operated in thereverse direction to facilitate the excavation of asphalt pavement andsimilar materials.

In accordance with the fourth embodiment of the invention describedherein, the excavating wheel assembly of an excavating and loadingsystem incorporating the invention is mounted for rotation about an axiswhich is angularly displaced from a line extending perpendicularly tothe longitudinal axis of the system. This is to prevent the formation ofridges between the excavating wheels of the excavating wheel assemblyduring the excavation of hard materials. The present application furtherdiscloses the use of conical cutter members secured to the outsideexcavating wheels of the excavating wheel assembly of an excavating andloading system incorporating the invention so as to form an excavationhaving tapered side walls.

Although particular embodiments of the invention have been illustratedin the accompanying drawings and described in the foregoing detaileddescription, it will be understood that the invention is not limited tothe embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions of parts and elements without departingfrom the spirit of the invention.

What is claimed is:

1. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and at least tworigid excavating wheels rotatably mounted cantilever on and supported onthe axle means, said excavating wheel assembly having a width at leastequal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging bucketslocated immediately adjacent one another to define the entirecircumference of the excavating wheel, each bucket having a cutting edgewhich extends to a stationary wall and a wall mounted for pivotalmovement from a material receiving position to a material dumpingposition;

supporting and housing means extending between the excavating wheels andconnected to the axle means for supporting the excavating wheelassembly;

each of said digging buckets extending continuously between a side wallthereof located immediately adjacent to the supporting means and a sidewall thereof defining one end of the excavating wheel assembly;

drive means extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path;

said digging buckets being oriented and said drive means operating tomove each digging bucket downwardly during the forward portion of itsrotation such that the digging buckets are sequentially moved downwardlyinto engagement with material to be excavated whereby the materialengaged by the digging buckets is supported by the ground below therebyallowing the digging buckets to cut off relatively small pieces of thematerial;

means located within the margins of the excavating wheel assembly andresponsive to rotation of the excavating wheels for positively pivotingthe movable wall of each digging bucket of the excavating wheels to thematerial receiving position when the bucket is in the lower and forwardportion of the path and for positively pivoting the movable wall to thematerial dumping position when the bucket is in the upper and rearwardportion of the path;

a vehicle for supporting and manipulating the excavating wheelsupporting means and thereby positioning the excavating wheel assemblyin engagement with material to be excavated; and

conveyor means mounted on the vehicle entirely behind the excavatingwheel assembly for movement around a course including a relatively lowportion positioned to receive material from the digging buckets of theexcavating wheels upon the positioning of the movable walls of thebuckets in the material dumping position and a relatively high materialdelivery portion located rearwardly on the vehicle from the low portion.

2. The excavating and loading system according to claim I furtherincluding a third excavating wheel supported on the axle means betweenthe two cantilever supported excavating wheels, and wherein theexcavating wheel supporting and driving means comprises spaced, parallelexcavating wheel supporting and driving means extending between thecenter and the two side excavating wheels.

3. The excavating and loading system according to claim 2 wherein theconveyor means receives material from the center excavating wheel andfurther including means mounted on the vehicle behind the excavatingwheel means for receiving material from the two side excavating wheelsand for directing the material to the conveyor means for transportationthereby to the discharge point.

4. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and three rigidexcavating wheels rotatably supported on the axle means, said excavatingwheel assembly having a width at least equal to the widest portion ofthe remainder of the system;

each of said excavating wheels including a plurality of digging buckets,each bucket having a cutting edge which extends to a stationary wall,and a wall mounted for pivotal movement from a material receivingposition to a material dumping position;

supporting and housing means extending between the excavating wheels andconnected to the axle means for supporting the excavating wheelassembly;

said three excavating wheels including a center excavating wheelcomprising digging buckets spanning continuously between pointsimmediately adjacent to the supporting and housing means and two sideexcavating wheels each comprising digging buckets spanning continuouslyfrom points immediately adjacent to the supporting and housing means topoints defining the outer ends of the excavating wheel assembly;

means including a drive mechanism extending through the supporting andhousing means for rotating the excavating wheels so that the diggingbuckets follow a circular path;

said digging buckets being oriented and said drive means operating tomove each digging bucket downwardly during the forward portion of itsrotation such that the digging buckets are sequentially moved downwardlyinto engagement with material to be excavated whereby the materialengaged by the digging buckets is supported by the ground below therebyallowing the digging buckets to cut off relatively small pieces of thematerial;

means located within the margins of the excavating wheel assembly andresponsive to rotation of the excavating wheels for positively pivotingthe movable wall of each bucket of the excavating wheels to the materialreceiving position when the bucket is in the lower and forward portionof the path and for positively pivoting the movable wall to the materialdumping position when the bucket is in the upper and rearward portion ofthe path;

a vehicle for supporting and manipulating the excavating wheelsupporting means and thereby positioning the excavating wheel assemblyin engagement with material to be excavated;

conveyor means mounted on the vehicle behind the excavating wheelassembly for movement around a course including a relatively low portionpositioned to receive material from each digging bucket of the centerexcavating wheel upon the positioning of the movable wall of the bucketin the material dumping position and a relatively high material deliveryportion located rearwardly on the vehicle from the lower portion; and

means positioned on the vehicle behind the excavating wheel assembly toreceive material from each digging bucket of the outside excavatingwheels upon the positioning of the movable wall of the bucket in thematerial dumping position and for directing the material to the conveyormeans.

5. The excavating and loading system according to claim 4 furtherincluding a conveyor frame supported on the main frame of the vehicleand extending angularly upwardly with respect thereto to define a courseof the conveyor means, means supporting the upper portion of theconveyor frame for pivotal movement with respect to the lower portionthereof, an auxiliary conveyor supported at the rear end of the systemfor receiving material from the conveyor means, and means supporting theauxiliary conveyor for pivotal movement about a vertical axis.

6. The excavating and loading system according to claim 4 wherein themovable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wallof one of the buckets;

a chain interconnecting the ends of the push rods remote from themovable walls; and

a member fixedly supported at a point over the material receivingportion of the conveyor means for cooperation with each push rod to movethe corresponding movable wall to the material dumping position.

7. The excavating and loading system according to claim 4 wherein themovable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wallof one of the buckets;

a collar connected to the ends of the push rods remote from the movablewalls;

means constraining the push rods to rotation with the buckets; and

means rotatably supporting the collar at a point offset from the axis ofrotation of the buckets and thereby actuating the push rods to pivot themovable walls to the material dumping position when their respectivebuckets are positioned over the material receiving portion of theconveyor means.

8. The excavating and loading system according to claim 4 wherein themovable wall pivoting means comprises:

a spring connected to each movable wall for normally positioning themovable wall in the material receiving position;

a cam mounted on each movable wall; and

means positioned over the material receiving portion of the conveyormeans for cooperation with the cams on the movable walls to pivot themovable walls to the material dumping position against the action of thesprings.

9. The excavating and loading system according to claim 4 wherein themovable wall pivoting means further comprises:

a cam track disposed around the axis of rotation of the buckets; and

a plurality of cam followers each connected to one of the movable wallsand each operatively engaged with the cam track for actuation thereby topivot the movable walls between the material receiving and the materialdumping positions.

10. The excavating and loading system according to claim 4 wherein themovable wall pivoting means comprises:

a plurality of cylinders each connected to one of the movable walls foractuation under fluid pressure to pivot the movable walls to thematerial dumping position; and

vavle means for controlling the actuation of the cylinders in accordancewith the rotational positioning of the digging buckets.

11. The excavating and loading system according to claim 4 furtherincluding:

auxiliary conveyor means mounted for pivotal movement about a verticalaxis; and

ballast means for selective actuation to counterbalance the auxiliaryconveyor means.

12. The excavating and loading system according to claim 4 wherein themeans for directing material from the two outside excavating wheels tothe conveyor means includes cross conveyors for transporting excavatedmaterial inwardly to the conveyor means.

13. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and at least tworigid excavating wheels rotatably mounted cantilever on and supported onthe axle means, said excavating wheel assembly having a width at leastequal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging bucketslocated immediately adjacent one another to define the entirecircumference of the excavating wheels, each bucket having a cuttingedge which extends to a stationary wall, and a wall mounted for pivotalmovement from a material receiving position to a material dumpingposition;

supporting and housing means extending between the excavating wheels andconnected to the axle means for supporting the excavating wheelassembly;

each of said digging buckets extending continuously between a side wallthereof located immediately adjacent to the supporting means and a sidewall thereof defining one end of the excavating wheel assembly;

drive means extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path;

said drive means including drive chain means mounted for movement arounda course extending in part through the supporting and housing means, arelatively large diameter sprocket mounted in the supporting and housingmeans and driven by the drive chain means, a relatively small diameterpinion driven by the sprocket, and a ring gear mounted on one of theexcavating wheels and driven by the pinion;

means located within the margins of the excavating wheel assembly andresponsive to rotation of the excavating wheels for positively pivotingthe movable wall of each digging bucket of the excavating wheels to thematerial receiving position when the bucket is in the lower and forwardportion of the path and for positively pivoting the movable wall to thematerial dumping position when the bucket is in the upper and rearwardportion of the path; vehicle for supporting and manipulating theexcavating wheel supporting means and thereby posi-

1. An excavating and loading system comprising: an excavating wheelassembly comprising axle means and at least two rigid excavating wheelsrotatably mounted cantilever on and supported on the axle means, saidexcavating wheel assembly having a width at least equal to the widestportion of the remainder of the system; each of said excavating wheelsincluding a plurality of digging buckets located immediately adjacentone another to define the entire circumference of the excavating wheel,each bucket having a cutting edge which extends to a stationary wall anda wall mounted for pivotal movement from a material receiving positionto a material dumping position; supporting and housing means extendingbetween the excavating wheels and connected to the axle means forsupporting the excavating wheel assembly; each of said digging bucketsextending continuously between a side wall thereof located immediatelyadjacent to the supporting means and a side wall thereof defining oneend of the excavating wheel assembly; drive means extending through thesupporting and housing means for rotating the excavating wheels so thatthe digging buckets follow a circular path; said digging buckets beingoriented and said drive means operating to move each digging bucketdownwardly during the forward portion of its rotation such that thedigging buckets are sequentially moved downwardly into engagement withmaterial to be excavated whereby the material engaged by the diggingbuckets is supported by the ground below thereby allowing the diggingbuckets to cut off relatively small pieces of the material; meanslocated within the margins of the excavating wheel assembly andresponsive to rotation of the excavating wheels for positively pivotingthe movable wall of each digging bucket of the excavating wheels to thematerial receiving position when the bucket is in the lower and forwardportion of the path and for positively pivotiNg the movable wall to thematerial dumping position when the bucket is in the upper and rearwardportion of the path; a vehicle for supporting and manipulating theexcavating wheel supporting means and thereby positioning the excavatingwheel assembly in engagement with material to be excavated; and conveyormeans mounted on the vehicle entirely behind the excavating wheelassembly for movement around a course including a relatively low portionpositioned to receive material from the digging buckets of theexcavating wheels upon the positioning of the movable walls of thebuckets in the material dumping position and a relatively high materialdelivery portion located rearwardly on the vehicle from the low portion.2. The excavating and loading system according to claim 1 furtherincluding a third excavating wheel supported on the axle means betweenthe two cantilever supported excavating wheels, and wherein theexcavating wheel supporting and driving means comprises spaced, parallelexcavating wheel supporting and driving means extending between thecenter and the two side excavating wheels.
 3. The excavating and loadingsystem according to claim 2 wherein the conveyor means receives materialfrom the center excavating wheel and further including means mounted onthe vehicle behind the excavating wheel means for receiving materialfrom the two side excavating wheels and for directing the material tothe conveyor means for transportation thereby to the discharge point. 4.An excavating and loading system comprising: an excavating wheelassembly comprising axle means and three rigid excavating wheelsrotatably supported on the axle means, said excavating wheel assemblyhaving a width at least equal to the widest portion of the remainder ofthe system; each of said excavating wheels including a plurality ofdigging buckets, each bucket having a cutting edge which extends to astationary wall, and a wall mounted for pivotal movement from a materialreceiving position to a material dumping position; supporting andhousing means extending between the excavating wheels and connected tothe axle means for supporting the excavating wheel assembly; said threeexcavating wheels including a center excavating wheel comprising diggingbuckets spanning continuously between points immediately adjacent to thesupporting and housing means and two side excavating wheels eachcomprising digging buckets spanning continuously from points immediatelyadjacent to the supporting and housing means to points defining theouter ends of the excavating wheel assembly; means including a drivemechanism extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path; said digging buckets being oriented and said drive meansoperating to move each digging bucket downwardly during the forwardportion of its rotation such that the digging buckets are sequentiallymoved downwardly into engagement with material to be excavated wherebythe material engaged by the digging buckets is supported by the groundbelow thereby allowing the digging buckets to cut off relatively smallpieces of the material; means located within the margins of theexcavating wheel assembly and responsive to rotation of the excavatingwheels for positively pivoting the movable wall of each bucket of theexcavating wheels to the material receiving position when the bucket isin the lower and forward portion of the path and for positively pivotingthe movable wall to the material dumping position when the bucket is inthe upper and rearward portion of the path; a vehicle for supporting andmanipulating the excavating wheel supporting means and therebypositioning the excavating wheel assembly in engagement with material tobe excavated; conveyor means mounted on the vehicle behind theexcavating wheel assembly for movement around a course including arelatively low portion positioned to receive material froM each diggingbucket of the center excavating wheel upon the positioning of themovable wall of the bucket in the material dumping position and arelatively high material delivery portion located rearwardly on thevehicle from the lower portion; and means positioned on the vehiclebehind the excavating wheel assembly to receive material from eachdigging bucket of the outside excavating wheels upon the positioning ofthe movable wall of the bucket in the material dumping position and fordirecting the material to the conveyor means.
 5. The excavating andloading system according to claim 4 further including a conveyor framesupported on the main frame of the vehicle and extending angularlyupwardly with respect thereto to define a course of the conveyor means,means supporting the upper portion of the conveyor frame for pivotalmovement with respect to the lower portion thereof, an auxiliaryconveyor supported at the rear end of the system for receiving materialfrom the conveyor means, and means supporting the auxiliary conveyor forpivotal movement about a vertical axis.
 6. The excavating and loadingsystem according to claim 4 wherein the movable wall pivoting meanscomprises: a plurality of push rods each connected at one end to themovable wall of one of the buckets; a chain interconnecting the ends ofthe push rods remote from the movable walls; and a member fixedlysupported at a point over the material receiving portion of the conveyormeans for cooperation with each push rod to move the correspondingmovable wall to the material dumping position.
 7. The excavating andloading system according to claim 4 wherein the movable wall pivotingmeans comprises: a plurality of push rods each connected at one end tothe movable wall of one of the buckets; a collar connected to the endsof the push rods remote from the movable walls; means constraining thepush rods to rotation with the buckets; and means rotatably supportingthe collar at a point offset from the axis of rotation of the bucketsand thereby actuating the push rods to pivot the movable walls to thematerial dumping position when their respective buckets are positionedover the material receiving portion of the conveyor means.
 8. Theexcavating and loading system according to claim 4 wherein the movablewall pivoting means comprises: a spring connected to each movable wallfor normally positioning the movable wall in the material receivingposition; a cam mounted on each movable wall; and means positioned overthe material receiving portion of the conveyor means for cooperationwith the cams on the movable walls to pivot the movable walls to thematerial dumping position against the action of the springs.
 9. Theexcavating and loading system according to claim 4 wherein the movablewall pivoting means further comprises: a cam track disposed around theaxis of rotation of the buckets; and a plurality of cam followers eachconnected to one of the movable walls and each operatively engaged withthe cam track for actuation thereby to pivot the movable walls betweenthe material receiving and the material dumping positions.
 10. Theexcavating and loading system according to claim 4 wherein the movablewall pivoting means comprises: a plurality of cylinders each connectedto one of the movable walls for actuation under fluid pressure to pivotthe movable walls to the material dumping position; and vavle means forcontrolling the actuation of the cylinders in accordance with therotational positioning of the digging buckets.
 11. The excavating andloading system according to claim 4 further including: auxiliaryconveyor means mounted for pivotal movement about a vertical axis; andballast means for selective actuation to counterbalance the auxiliaryconveyor means.
 12. The excavating and loading system according to claim4 wherein the means for directing material from the two outsideexcavating wheels to The conveyor means includes cross conveyors fortransporting excavated material inwardly to the conveyor means.
 13. Anexcavating and loading system comprising: an excavating wheel assemblycomprising axle means and at least two rigid excavating wheels rotatablymounted cantilever on and supported on the axle means, said excavatingwheel assembly having a width at least equal to the widest portion ofthe remainder of the system; each of said excavating wheels including aplurality of digging buckets located immediately adjacent one another todefine the entire circumference of the excavating wheels, each buckethaving a cutting edge which extends to a stationary wall, and a wallmounted for pivotal movement from a material receiving position to amaterial dumping position; supporting and housing means extendingbetween the excavating wheels and connected to the axle means forsupporting the excavating wheel assembly; each of said digging bucketsextending continuously between a side wall thereof located immediatelyadjacent to the supporting means and a side wall thereof defining oneend of the excavating wheel assembly; drive means extending through thesupporting and housing means for rotating the excavating wheels so thatthe digging buckets follow a circular path; said drive means includingdrive chain means mounted for movement around a course extending in partthrough the supporting and housing means, a relatively large diametersprocket mounted in the supporting and housing means and driven by thedrive chain means, a relatively small diameter pinion driven by thesprocket, and a ring gear mounted on one of the excavating wheels anddriven by the pinion; means located within the margins of the excavatingwheel assembly and responsive to rotation of the excavating wheels forpositively pivoting the movable wall of each digging bucket of theexcavating wheels to the material receiving position when the bucket isin the lower and forward portion of the path and for positively pivotingthe movable wall to the material dumping position when the bucket is inthe upper and rearward portion of the path; a vehicle for supporting andmanipulating the excavating wheel supporting means and therebypositioning the excavating wheel assembly in engagement with material tobe excavated; and conveyor means mounted on the vehicle entirely behindthe excavating wheel assembly for movement around a course including arelatively low portion positioned to receive material from the diggingbuckets of the excavating wheels upon the positioning of the movablewalls of the buckets in the material dumping position and a relativelyhigh material delivery portion located rearwardly on the vehicle fromthe low portion.
 14. The excavating and loading system according toclaim 13 further including a third excavating wheel supported on theaxle means between the two cantilever supported excavating wheels, andwherein the excavating wheel supporting and driving means comprisesspaced, parallel excavating wheel supporting and driving means extendingbetween the center and the two side excavating wheels.
 15. Theexcavating and loading system according to claim 14 wherein the conveyormeans receives material from the center excavating wheel and furtherincluding means mounted on the vehicle behind the excavating wheel meansfor receiving material from the two side excavating wheels and fordirecting the material to the conveyor means for transportation therebyto the discharge point.
 16. The excavating and loading system accordingto claim 13 further including: auxiliary conveyor means mounted on thevehicle for receiving excavated material from the conveyor means andmounted for pivotal movement about a vertical axis; a plurality ofballast tanks; and means for selectively directing liquid between theballast tanks to counterbalance the weight of the auxiliary conveyormeans.
 17. An excavating and loading system comprising: an excavatingwheel assembly comprising axle means and three rigid excavating wheelsrotatably supported on the axle means, said excavating wheel assemblyhaving a width at least equal to the widest portion of the remainder ofthe system; each of said excavating wheels including a plurality ofdigging buckets, each bucket having a cutting edge which extends to astationary wall, and a wall mounted for pivotal movement from a materialreceiving position to a material dumping position; supporting andhousing means extending between the excavating wheels and connected tothe axle means for supporting the excavating wheel assembly; said threeexcavating wheels including a center excavating wheel comprising diggingbuckets spanning continuously between points immediately adjacent to thesupporting and housing means and two side excavating wheels eachcomprising digging buckets spanning continuously from points immediatelyadjacent to the supporting and housing means to points defining theouter ends of the excavating wheel assembly; means including a drivemechanism extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path; said drive mechanism including drive chain means mountedfor movement around a course extending in part through the supportingand housing means, a relatively large diameter sprocket mounted in thesupporting and housing means and driven by the drive chain means, arelatively small diameter pinion driven by the sprocket, and a ring gearmounted on one of the excavating wheels and driven by the pinion; meanslocated within the margins of the excavating wheel assembly andresponsive to rotation of the excavating wheels for positively pivotingthe movable wall of each bucket of the excavating wheels to the materialreceiving position when the bucket is in the lower and forward portionof the path and for positively pivoting the movable wall to the materialdumping position when the bucket is in the upper and rearward portion ofthe path; a vehicle for supporting and manipulating the excavating wheelsupporting means and thereby positioning the excavating wheel assemblyin engagement with material to be excavated; conveyor means mounted onthe vehicle behind the excavating wheel assembly for movement around acourse including a relatively low portion positioned to receive materialfrom each digging bucket of the center excavating wheel upon thepositioning of the movable wall of the bucket in the material dumpingposition and a relatively high material delivery portion locatedrearwardly on the vehicle from the lower portion; and means positionedon the vehicle behind the excavating wheel assembly to receive materialfrom each digging bucket of the outside excavating wheels upon thepositioning of the movable wall of the bucket in the material dumpingposition and for directing the material to the conveyor means.
 18. Theexcavating and loading system according to claim 17 further including aconveyor frame supported on the main frame of the vehicle and extendingangularly upwardly with respect thereto to define a course of theconveyor means, means supporting the upper portion of the conveyor framefor pivotal movement with respect to the lower portion thereof, anauxiliary conveyor supported at the rear end of the system for receivingmaterial from the conveyor means, and means supporting the auxiliaryconveyor for pivotal movement about a vertical axis.
 19. The excavatingand loading system according to claim 18 further including a ballastsystem comprising a plurality of tanks positioned at spaced points onthe vehicle and means for selectively pumping liquid between the tanksand thereby counterbalancing the weight of the auxiliary conveyor. 20.The excavating and loading system according to claim 17 wherein themeans for directing material from the two outside excavating wheels tothe conveyor means includes cross conveyors for Transporting excavatedmaterial inwardly to the conveyor means.
 21. An excavating and loadingsystem comprising: an excavating wheel assembly comprising axle meansand at least two rigid excavating wheels rotatably mounted cantilever onand supported on the axle means, said excavating wheel assembly having awidth at least equal to the widest portion of the remainder of thesystem; each of said excavating wheels including a plurality of diggingbuckets located immediately adjacent one another to define the entirecircumference of the excavating wheel, each bucket having a cutting edgewhich extends to a stationary wall, and a wall mounted for pivotalmovement from a material receiving position to a material dumpingposition; supporting and housing means extending between the excavatingwheels and connected to the axle means for supporting the excavatingwheel assembly; each of said digging buckets extending continuouslybetween a side wall thereof located immediately adjacent to thesupporting means and a side wall thereof defining one end of theexcavating wheel assembly; drive means extending through the supportingand housing means for rotating the excavating wheels so that the diggingbuckets follow a circular path; the axis of rotation of the excavatingwheels being horizontally disposed and being angularly offset withrespect to a line extending perpendicular to the longitudinal axis ofthe vehicle so as to prevent the formation of ridges in the spacesbetween the excavating wheels; means located within the margins of theexcavating wheel assembly and responsive to rotation of the excavatingwheels for positively pivoting the movable wall of each digging bucketof the excavating wheels to the material receiving position when thebucket is in the lower and forward portion of the path and forpositively pivoting the movable wall to the material dumping positionwhen the bucket is in the upper and rearward portion of the path; avehicle for supporting and manipulating the excavating wheel supportingmeans and thereby positioning the excavating wheel assembly inengagement with material to be excavated; and conveyor means mounted onthe vehicle entirely behind the excavating wheel assembly for movementaround a course including a relatively low portion positioned to receivematerial from the digging buckets of the excavating wheels upon thepositioning of the movable walls of the buckets in the material dumpingposition and a relatively high material delivery portion locatedrearwardly on the vehicle from the low portion.
 22. The excavating andloading system according to claim 21 further including a thirdexcavating wheel supported on the axle means between the two cantileversupported excavating wheels, and wherein the excavating wheel supportingand driving means comprises spaced, parallel excavating wheel supportingand driving means extending between the center and the two sideexcavating wheels.
 23. The excavating and loading system according toclaim 22 wherein the conveyor means receives material from the centerexcavating wheel and further including means mounted on the vehiclebehind the excavating wheel means for receiving material from the twoside excavating wheels and for directing the material to the conveyormeans for transportation thereby to the discharge point.
 24. Theexcavating and loading system according to claim 21 further including aconveyor frame supported on the main frame of the vehicle and extendingangularly upwardly with respect thereto to define a course of theconveyor means, means supporting the upper portion of the conveyor framefor pivotal movement with respect to the lower portion thereof, anauxiliary conveyor supported at the rear end of the system for receivingmaterial from the conveyor means, and means supporting the auxiliaryconveyor for pivotal movement about a vertical axis.
 25. The excavatingand loading system according to claim 21 further including a ballasTsystem comprising a plurality of tanks positioned at spaced points onthe vehicle and means for selectively pumping liquid between the tanks.26. The excavating and loading system according to claim 21 wherein themovable wall pivoting means comprises: a plurality of push rods eachconnected at one end to the movable wall of one of the buckets; a chaininterconnecting the ends of the push rods remote from the movable walls;and a member fixedly supported at a point over the material receivingportion of the conveyor means for cooperation with each push rod to movethe corresponding movable wall to the material dumping position.
 27. Theexcavating and loading system according to claim 21 wherein the movablewall pivoting means comprises: a plurality of push rods each connectedat one end to the movable wall of one of the buckets; a collar connectedto the ends of the push rods remote from the movable walls; meansconstraining the push rods to rotation with the buckets; and meansrotatably supporting the collar at a point offset from the axis ofrotation of the buckets and thereby actuating the push rods to pivot themovable walls to the material dumping position when their respectivebuckets are positioned over the material receiving portion of theconveyor means.
 28. The excavating and loading system according to claim21 wherein the movable wall pivoting means comprises: a spring connectedto each movable wall for normally positioning the movable wall in thematerial receiving position; a cam mounted on each movable wall; andmeans positioned over the material receiving portion of the conveyormeans for cooperation with the cams on the movable walls to pivot themovable walls to the material dumping position against the action of thesprings.
 29. The excavating and loading system according to claim 21wherein the movable wall pivoting means further comprises: a cam trackdisposed around the axis of rotation of the buckets; and a plurality ofcam followers each connected to one of the movable walls and eachoperatively engaged with the cam track for actuation thereby to pivotthe movable walls between the material receiving and the materialdumping positions.
 30. The excavating and loading system according toclaim 21 wherein the movable wall pivoting means comprises: a pluralityof cylinders each connected to one of the movable walls for actuationunder fluid pressure to pivot the movable walls to the material dumpingposition; and valve means for controlling the actuation of the cylindersin accordance with the rotational positioning of the digging buckets.31. The excavating and loading system according to claim 21 furtherincluding: auxiliary conveyor means mounted on the vehicle for receivingexcavated material from the conveyor means and mounted for pivotalmovement about a vertical axis; a plurality of ballast tanks; and meansfor selectively directing liquid between the ballast tanks tocounterbalance the weight of the auxiliary conveyor means.
 32. Theexcavating and loading system according to claim 31 wherein the vehiclefurther comprises: a frame; means supporting the frame for movementalong a surface; and an engine for actuating the supporting means topropel the vehicle and for actuating the conveyor means and theauxiliary conveyor means; and wherein the ballast tanks are furthercharacterized by four ballast tanks positioned at forward and rearwardpositions on opposite sides of the frame.
 33. The excavating and loadingsystem according to claim 32 wherein the excavating wheel means ispositioned at one end of the frame, wherein the conveyor means extendsrearwardly from the frame between the ballast tanks, and wherein theauxiliary conveyor means is positioned at the opposite end of the framefrom the excavating wheel means.
 34. The excavating and loading systemaccording to claim 21 wherein the conveyor means comprises a pair ofcross conveyors mounted on the vehicle adjacent the excavating wheelsfor receiving material from the excavating wheels and for transportingthe material inwardly and a conveyor centrally disposed on the vehiclefor receiving material from the cross conveyors and from the excavatingwheels and for transporting the material angularly upwardly to adischarge point at the opposite end of the vehicle from the excavatingwheels.
 35. An excavating and loading system comprising: an excavatingwheel assembly comprising axle means and three rigid excavating wheelsrotatably supported on the axle means, said excavating wheel assemblyhaving a width at least equal to the widest portion of the remainder ofthe system; each of said excavating wheels including a plurality ofdigging buckets, each bucket having a cutting edge which extends to astationary wall, and a wall mounted for pivotal movement from a materialreceiving position to a material dumping position; supporting andhousing means extending between the excavating wheels and connected tothe axle means for supporting the excavating wheel assembly; said threeexcavating wheels including a center excavating wheel comprising diggingbuckets spanning continuously between points immediately adjacent to thesupporting and housing means and two side excavating wheels eachcomprising digging buckets spanning continuously from points immediatelyadjacent to the supporting and housing means to points defining theouter ends of the excavating wheel assembly; means including a drivemechanism extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path; the axis of rotation of the excavating wheels beinghorizontally disposed and being angularly offset with respect to a lineextending perpendicular to the longitudinal axis of the vehicle so as toprevent the formation of ridges in the spaces between the excavatingwheels; means located within the margins of the excavating wheelassembly and responsive to rotation of the excavating wheels forpositively pivoting the movable wall of each bucket of the excavatingwheels to the material receiving position when the bucket is in thelower and forward portion of the path and for positively pivoting themovable wall to the material dumping position when the bucket is in theupper and rearward portion of the path; a vehicle for supporting andmanipulating the excavating wheel supporting means and therebypositioning the excavating wheel assembly in engagement with material tobe excavated; conveyor means mounted on the vehicle behind theexcavating wheel assembly for movement around a course including arelatively low portion positioned to receive material from each diggingbucket of the center excavating wheel upon the positioning of themovable wall of the bucket in the material dumping position and arelatively high material delivery portion located rearwardly of thevehicle from the lower portion; and means positioned on the vehiclebehind the excavating wheel assembly to receive material from eachdigging bucket of the outside excavating wheels upon the positioning ofthe movable wall of the bucket in the material dumping position and fordirecting the material to the conveyor means.
 36. The excavating andloading system according to claim 35 further including a conveyor framesupported on the main frame of the vehicle and extending angularlyupwardly with respect thereto to define a course of the conveyor means,means supporting the upper portion of the conveyor frame for pivotalmovement with respect to the lower portion thereof, an auxiliaryconveyor supported at the rear end of the system for receiving materialfrom the conveyor means, and means supporting the auxiliary conveyor forpivotal movement about a vertical axis.
 37. The excavating and loadingsystem according to claim 36 further including a ballast systemcomprising a plurality of tankS positioned at spaced points on thevehicle and means for selectively pumping liquid between the tanks andthereby counterbalancing the weight of the auxiliary conveyor.
 38. Theexcavating and loading system according to claim 35 wherein the meansfor directing material from the two outside excavating wheels to theconveyor means includes cross conveyors for transporting excavatedmaterial inwardly to the conveyor means.
 39. An excavating and loadingsystem comprising: vehicle means having a main frame and adapted formovement over a surface and having a predetermined length and apredetermined width; excavating wheel means mounted at the front end ofthe vehicle means for rotation about an axis extending parallel to thewidth and perpendicular to the length of the vehicle; said excavatingwheel means comprising axle means, two rigid side excavating wheelsmounted cantilever on the axle means and comprising and outermoststructural components of the excavating and loading system, a thirdrigid excavating wheel supported on the axle means and extending betweenthe two side excavating wheels and spaced, parallel excavating wheelsupporting and housing means extending between the center and the twoside excavating wheels; means including a drive mechanism extendingthrough the supporting and housing means for rotating and excavatingwheels so that the digging buckets follow a circular path; the axis ofrotation of the excavating wheels being horizontally disposed and beingangularly offset with respect to a line extending perpendicular to thelongitudinal axis of the vehicle so as to prevent the formation ofridges in the spaces between the excavating wheels; each of saidexcavating wheels further comprising a plurality of digging buckets withthe digging buckets of the side excavating wheels spanning continuouslyfrom the outer ends of the excavating wheel means to points immediatelyadjacent the supporting and housing means and with the digging bucketsof the center excavating wheel spanning continuously between pointsimmediately adjacent the two supporting and housing means; the diggingbuckets each comprising a rear wall mounted for movement between amaterial receiving position and a material discharging position; meanslocated within the margins of the excavating wheel means and responsiveto rotation of the excavating wheel means relative to the vehicle forfirst positively actuating the movable wall of each digging bucket tothe material receiving position and for subsequently positivelyactuating the movable wall of each digging bucket to the materialdischarging position; conveyor means mounted on the vehicle behind theexcavating wheel means for receiving material from the center excavatingwheel and for carrying the material upwardly and rearwardly to adischarge point at the rear end of the vehicle; and means mounted on thevehicle behind the excavating wheel means for receiving material fromthe two side excavating wheels and for directing the material to theconveyor means for transportation thereby to the discharge point.
 40. Anexcavating and loading system comprising: an excavating wheel assemblycomprising axle means and at least two rigid excavating wheels rotatablymounted cantilever on and supported on the axle means, said excavatingwheel assembly having a width at least equal to the widest portion ofthe remainder of the system; each of said excavating wheels including aplurality of digging buckets located immediately adjacent one another todefine the entire circumference of the excavating wheel, each buckethaving a cutting edge which extends to a stationary wall, and a wallmounted for pivotal movement from a material receiving position to amaterial dumping position; supporting and housing means extendingbetween the excavating wheels and connected to the axle means forsupporting the excavating wheel assembly; each of said digging bucketsextending continuously between a side wall thereof located immediatelyadjacent to the supporting means and a side wall thereof defining oneend of the excavating wheel assembly; drive means extending through thesupporting housing means for rotating the excavating wheels so that thedigging buckets follow a circular path; means located within the marginsof the excavating wheel assembly and responsive to rotation of theexcavating wheels for positively pivoting the movable wall of eachdigging bucket of the excavating wheels to the material receivingposition when the bucket is in the lower and forward portion of the pathand for positively pivoting the movable wall to the material dumpingposition when the bucket is in the upper and rearward portion of thepath; a vehicle for supporting and manipulating the excavating wheelsupporting means and thereby positioning the excavating wheel assemblyin engagement with material to be excavated; conveyor means mounted onthe vehicle entirely behind the excavating wheel assembly for movementaround a course including a relatively low portion positioned to receivematerial from the digging buckets of the excavating wheels upon thepositioning of the movable walls of the buckets in the material dumpingposition and a relatively high material delivery portion locatedrearwardly on the vehicle from the low portion; and conical cutter meansdetachably secured to the two excavating wheels and extending inopposite directions therefrom for rotating with the excavating wheelsunder the action of the drive means.
 41. An excavating and loadingsystem comprising: an excavating wheel assembly comprising axle meansand three rigid excavating wheels rotatably supported on the axle means,said excavating wheel assembly having a width at least equal to thewidest portion of the remainder of the system; each of said excavatingwheels including a plurality of digging buckets, each bucket having acutting edge which extends to a stationary wall, and a wall mounted forpivotal movement from a material receiving position to a materialdumping position; supporting and housing means extending between theexcavating wheels and connected to the axle means for supporting theexcavating wheel assembly; said three excavating wheels including acenter excavating wheel comprising digging buckets spanning continuouslybetween points immediately adjacent to the supporting and housing meansand two side excavating wheels each comprising digging buckets spanningcontinuously from points immediately adjacent to the supporting andhousing means to points defining the outer ends of the excavating wheelassembly; means including a drive mechanism extending through thesupporting and housing means for rotating the excavating wheels so thatthe digging buckets follow a circular path; means located within themargins of the excavating wheel assembly and responsive to rotation ofthe excavating wheels for positively pivoting the movable wall of eachbucket of the excavating wheels to the material receiving position whenthe bucket is in the lower and forward portion of the path and forpositively pivoting the movable wall to the material dumping positionwhen the bucket is in the upper and rearward portion of the path; avehicle for supporting and manipulating the excavating wheel supportingmeans and thereby positioning the excavating wheel assembly inengagement with material to be excavated; conveyor means mounted on thevehicle behind the excavating wheel assembly for movement around acourse including a relatively low portion positioned to receive materialfrom each digging bucket of the center excavating wheel upon thepositioning of the movable wall of the bucket in the material dumpingposition and a relatively high material delivery portion locatedrearwardly on the vehicle from the lower portion; means positioned onthe vehicle behind the excavating wheel assembly to receive materialfrom each digging bucket of the outsiDe excavating wheels upon thepositioning of the movable wall of the bucket in the material dumpingposition and for directing the material to the conveyor means; andconical cutter means detachably secured to the outside two excavatingwheels and extending in opposite directions therefrom for rotation withthe excavating wheels under the action of the drive mechanism.
 42. Anexcavating and loading system comprising: vehicle means having a mainframe and adapted for movement over a surface and having a predeterminedlength and a predetermined width; excavating wheel means mounted at thefront end of the vehicle means for rotation about an axis extendingparallel to the width and perpendicular to the length of the vehicle;said excavating wheel means comprising axle means, two rigid sideexcavating wheels mounted cantilever on the axle means and comprisingthe outermost structural components of the excavating and loadingsystem, a third rigid excavating wheel supported on the axle means andextending between the two side excavating wheels and spaced, parallelexcavating wheel supporting and housing means extending between thecenter and the two side excavating wheels; means including a drivemechanism extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path; each of said excavating wheels further comprising aplurality of digging buckets with the digging buckets of the sideexcavating wheels spanning continuously from the outer ends of theexcavating wheel means to points immediately adjacent the supporting andhousing means and with the digging buckets of the center excavatingwheel spanning continuously between points immediately adjacent the twosupporting and housing means; the digging buckets each comprising a rearwall mounted for movement between a material receiving position and amaterial discharging position. means located within the margins of theexcavating wheel means and responsive to rotation of the excavatingwheel means relative to the vehicle for first positively actuating themovable wall of each digging bucket to the material receiving positionand for subsequently positively actuating the movable wall of eachdigging bucket to the material discharging position; conveyor meansmounted on the vehicle behind the excavating wheel means for receivingmaterial from the center excavating wheel and for carrying the materialupwardly and rearwardly to a discharge point at the rear end of thevehicle; means mounted on the vehicle behind the excavating wheel meansfor receiving material from the two side excavating wheels and fordirecting the material to the conveyor means for transportation therebyto the discharge point; and conical cutter means detachably secured tothe outside two excavating wheels and extending in opposite directionstherefrom for rotation with the excavating wheels under the action ofthe drive mechanism.
 43. An excavating and loading system comprising: anexcavating wheel assembly comprising axle means and at least two rigidexcavating wheels rotatably mounted cantilever on and supported on theaxle means, said excavating wheel assembly having a width at least equalto the widest portion of the remainder of the system; each of saidexcavating wheels including a plurality of digging buckets locatedimmediately adjacent one another to define the entire circumference ofthe excavating wheel, each bucket having a cutting edge which extends toa stationary wall, and a wall mounted for pivotal movement from amaterial receiving position to a material dumping position; supportingand housing means extending between the excavating wheels and connectedto the axle means for supporting the excavating wheel assembly; saidaxle means comprising separate axle portions each rotatably supportingone of the excavating wheels and each detachably secured to thesupporting and housing means; each Of said digging buckets extendingcontinuously between a side wall thereof located immediately adjacent tothe supporting means and a side wall thereof defining one end of theexcavating wheel asssembly; drive means extending through the supportingand housing means for rotating the excavating wheels so that the diggingbuckets follow a circular path; means located within the margins of theexcavating wheel assembly and responsive to rotation of the excavatingwheels for positively pivoting the movable wall of each digging bucketof the excavating wheels to the material receiving position when thebucket is in the lower and forward portion of the path and forpositively pivoting the movable wall to the material dumping positionwhen the bucket is in the upper and rearward portion of the path; avehicle for supporting and manipulating the excavating wheel supportingmeans and thereby positioning the excavating wheel assembly inengagement with material to be excavated; and conveyor means mounted onthe vehicle entirely behind the excavating wheel assembly for movementaround a course including a relatively low portion positioned to receivematerial from the digging buckets of the excavating wheels upon thepositioning of the movable walls of the buckets in the material dumpingposition and a relatively high material delivery portion locatedrearwardly on the vehicle from the low portion.
 44. An excavating andloading system comprising: an excavating wheel assembly comprising axlemeans and three rigid excavating wheels rotatably supported on the axlemeans, said excavating wheel assembly having a width at least equal tothe widest portion of the remainder of the system; each of saidexcavating wheels including a plurality of digging buckets, each buckethaving a cutting edge which extends to a stationary wall, and a wallmounted for pivotal movement from a material receiving position to amaterial dumping position; supporting and housing means extendingbetween the excavating wheels and connected to the axle means forsupporting the excavating wheel assembly; said axle means comprisingseparate axle portions each rotatably supporting one of the excavatingwheels and each detachably secured to the supporting and housing means;said three excavating wheels including a center excavating wheelcomprising digging buckets spanning continuously between pointsimmediately adjacent to the supporting and housing means and two sideexcavating wheels each comprising digging buckets spanning continuouslyfrom points immediately adjacent to the supporting and housing means topoints defining the outer ends of the excavating wheel assembly; meansincluding a drive mechanism extending through the supporting and housingmeans for rotating the excavating wheels so that the digging bucketsfollow a circular path; means located within the margins of theexcavating wheel assembly and responsive to rotation of the excavatingwheels for postively pivoting the movable wall of each bucket of theexcavating wheels to the material receiving position when the bucket isin the lower and forward portion of the path and for positively pivotingthe movable wall to the material dumping postion when the bucket is inthe upper and rearward portion of the path; a vehicle for supporting andmanipulating the excavating wheel supporting means and therebypositioning the excavating wheel assembly in engagement with material tobe excavated; conveyor means mounted on the vehicle behind theexcavating wheel assembly for movement around a course including arelatively low portion positioned to receive material from each diggingbucket of the center excavating wheel upon the positioning of themovable wall of the bucket in the material dumping position and arelatively high material delivery portion located rearwardly on thevehicle from the lower portion; and means positioned on the vehiclebehind the excavating wheel assembly to receive material from eachdigging bucket of the outside excavating wheels upon the positioning ofthe movable wall of the bucket in the material dumping position and fordirecting the material to the conveyor means.
 45. An excavating andloading system comprising: vehicle means having a main frame and adaptedfor movement over a surface and having a predetermined length and apredetermined width; excavating wheel means mounted at the front end ofthe vehicle means for rotation about an axis extending parallel to thewidth and perpendicular to the length of the vehicle; said excavatingwheel means comprising axle means, two rigid side excavating wheelsmounted cantilever on the axle means and comprising the outermoststructural components of the excavating and loading system, a thirdrigid excavating wheel supported on the axle means and extending betweenthe two side excavating wheels and spaced, parallel excavating wheelsupporting and housing means extending between the center and the twoside excavating wheels; said axle means comprising separate axleportions each rotatably supporting one of the excavating wheels and eachdetachably secured to the supporting and housing means; means includinga drive mechanism extending through the supporting and housing means forrotating the excavating wheels so that the digging buckets follow acircular path; each of said excavating wheels further comprising aplurality of digging buckets with the digging buckets of the sideexcavating wheels spanning continuously from the outer ends of theexcavating wheel means to points immediately adjacent the supporting andhousing means and with the digging buckets of the center excavatingwheel spanning continuously between points immediately adjacent the twosupporting and housing means; the digging buckets each comprising a rearwall mounted for movement between a material receiving position and amaterial discharging position; means located within the margins of theexcavating wheel means and responsive to rotation of the excavatingwheel means relative to the vehicle for first positively actuating themovable wall of each digging bucket to the material receiving positionand for subsequently positively actuating the movable wall of eachdigging bucket to the material discharging position; conveyor meansmounted on the vehicle behind the excavating wheel means for receivingmaterial from the center excavating wheel and for carrying the materialupwardly and rearwardly to a discharge point at the rear end of thevehicle; and means mounted on the vehicle behind the excavating wheelmeans for receiving material from the two side excavating wheels and fordirecting the material to the conveyor means for transportation therebyto the discharge point.